NEPLAN | Cable Sizing

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This module is used for the selection of the type and cross-sectional area of a cable as well as the protection device for an assumed passive or motor load and a given infeed. The cable type can be selected either from the predefined cable library within NEPLAN or from user-defined cable libraries depending on various international standards such as VDE, IEC, NEC, etc. The basic principle underlying cable sizing calculations remains the same for all these standards. However, it is important to consider the geographical conditions and then select an appropriate standard. The module can also be used for the inspection of already installed cables.

General Characteristics

  • Automatic selection of protection device rating and setting. Device is taken from NEPLAN protection library
  • Sizing of one cable or any number of cables together (distributed radial network)
  • Maximum length of selected cable type and section for which the criteria is still fulfilled

Criteria of dimensioning

  • Service current of consumer, influence current rating of cable
  • Protection of cable against overload
  • Tolerable voltage drop and voltage limits
  • Protection against hazardous voltage (people protection), influence switch off in tolerable time
  • Protection of cable against short-term overheating


Proper dimensioning of cables ensures that they can:

  • Operate continuously under normal operating load conditions without getting overloaded
  • Operate continuously during motor-starting operation if applicable
  • Switch-off within defined time for minimum short-circuit current in a network
  • Withstand maximum short-circuit current to avoid thermal damage of the cable
  • Provide downstream loads with proper operating voltage by making sure there is no excessive voltage drop in the cables

Apart from the cable cross-section area and the maximum cable length, the module provides with further results, including voltage drop condition for normal and motor start operation, criteria for overload and short-circuit protection, tripping times etc.